Improvement in tan-vats



UNITED STATES PATENT QFFIGE.

IMPROVEMENT IN TAN-VATS.

Specification forming part of Letters Patent No. 135,231, dated January 28, 1873.

.To all whom it may concern: I

Be it known that I, CHARLES H. MANNING,

. of Washington, in the county of Washington and'District of Columbia, have invented certain'Improvements in Vats for Tanning Leather, in cacao and-under pressure, separately or combined; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing making part of this specification- Figure 1 being a top view of the improved vat,one of its covers being removed; Fig. 2,

a longitudinal vertical section thereof; Fig. 3, a transverse vertical section of the same.

Like letters designate corresponding parts in all of the figures.

My invention consists in certain improvements in the construction of tan-vats, for'the purpose of adapting them most perfectly to the process of tanning to mono and under pressure, successively or separately, as hereinafter specified.

' First, my purpose is to adapt vats of ordinary size, shape, and material, so as to be air and. water tight, and to perform the whole process therein, and dispense with outside vessels or compartments. Thus I employ the ordinary material, wood, which is cheap and well enough adapted to the purpose, provided that the vats constructed thereof can be rendered impervious to air and water, so that either a vacuum or a strong pressure may be produced therein.

To renderthe sides and bottom of the vats thus impervious to air and water they are made of two or more thicknesses or layers of the wood, a b c, and between adjacent thicknesses thereof, a thickness, d, of metal, preferably lead, is placed it being thus securely held in place, being neither an inside nor outside lining, the former of which would be liable to be drawn off or away from the wood by the pressure from without, and the latter would be liable to tear off by the pressure from within outward. In addition to the thickness of metal a layer of thick paper may be placed next to the same, so that increased firmness is added thereto, and a less thickness and cost of metal will suffice. Another thickness, g, of paper may be placed between other thicknesses of the wood, as shown, and more thicknesses might be employed,if necessary.

In order to protect the paper and the surfaces of the metal from destruction or corrosion and to render the paper impervious and water-proof, I apply a protective varnish or coating upon the surfaces thereof. The ingredients of the varnish or coating which-I employ, and prefer on account of its superior qualities for the purpose, are bees-wax and spirits of turpentine, in the proportion of about two pounds of bees-wax to one gallon of the spirits of turpentine, or so as to give to the mixture the proper consistence for spreading on with a brush. In preparing the composition the bees-wax is first melted and removed from the fire before the spirits of turpentine is added thereto.

In the adaptation of the vats to the use of the vacuum and pressure process, although there is increased difficulty in applying large covers thereto and packing them tightly, yet it is very desirable to remove the entire top of the vats for putting in and taking out the hides, and handling them therein, and not to confine the entrance to a mere man-hole. In my invention I remove the whole top of each vat or division of a vat, there being two or more divisions, B C, in the oblong vat, as shown. In order to properly pack the top or coverAupon the vat, a groove or depression, h, is made in the top of the same, all around the opening, as shown, this groove being easily formed, when the sides of the vat are made of three thicknesses, by leaving the middle thickness somewhat lower than the others; but the groove may be formed in any other convenient way. The cover A has a projecting rim, 2 which fits or reaches down into the groove h, and it has a packing strip or gasket, 1, of India rubber, or equivalent material, secured upon the lower edge to lie upon the bottom of the groove h; and there is another p'acking strip or gasket, m, upon the under side of the cover, inside of its rim 6, to rest upon the inner projection n of the vat, sothat there is a double security in the packing.

The packing strip or gasket 1 projects laterally beyond both edges of the rim 2', so that the pressure of the air outside may make the packing press more tightly upon its sealing-surface, and in the same manner the atmosphere inside, when pressure is used,has the same effeet; and in addition to the packing strips or gaskets 1 use a soft packing or substance impervious to air to fill the groove h around the rim 1' of the cover.

I find that common bar soap is a very suitable material for this purpose, and is cheap and convenient in use. It is first melted, and then poured into the groove after the cover has been applied to the vat. It is easily removed,

- and can be used again and again with little loss.

The cover is fastened upon the vat so as to resist inside pressure by means of loops or eyes 0 o, cross-bars p p, and wedges or screws r r, or any equivalent means.

The covers A A are or may be constructed of thicknesses of wood, with intermediate thicknesses or layers of lead and paper, as described above for the body of the vat.

The covers are applicable to vats of ordinary construction already in use, particularly to cement vats, the packing-groove being formed in the top thereof in any suitable and convenient manner.

In addition to the removable air and water tight covers A A, I make a man-hole, s, in each cover, and secure by screws or otherwise a tight lid, t, thereon, so that access may be had to the interior of the vat, for inspection or other purpose other than putting in and taking out the hides and skins, more conveniently than by removing the whole cover. Under the covers A A racks or frames D D are situated in the top of the vat or vat sections to suspend the hides and skins from. These racks are made so as to be lifted out of the vats with all the hides suspended therefrom, and introduced into the vats by employing suitable tackle or other hoisting device for the purpose.

In order to conduct the operation of tanning more rapidly and uniformly the tan liquor with in the vats should be kept in motion or frequently agitated; but the close covering of the vats renders it somewhat difiicult to produce this agitation from without and not disturb the vacuum or pressure within, as the case may be. I apply one or more paddles or agitators, E E, of any convenient form, inside of the vat, as represented, the same being pivoted so as to be capable of' a vibratory movement up and down, or otherwise. Aconnecting-rod, it, extends from the agitator E through a hole in the top of the vat, with a suitable packing around it, so as to prevent leakage of air in or out. To this connectingrod power may be applied in various ways, so as-to produce a reciprocating movement of the agitators without disturbing the vacuum or pressure within. The agitators are connected by a rod so as to move simultaneously. They are located at the end of the vat, or between two divisions of the vat, as represented, so that their position does not interfere with the hides in the vat; By their location one above the other, and their vibration across the vat, they cause the agitation of all the liquor in the vat, so as to induce the necessary circulation thereof through the same and be tween the hides. A single tube or pipe, G, entering the vat suffices for both exhausting the air from and forcing the air into the vat by using in connection with it a pump constructed both for exhausting and condensing; or two pumps may be used, if preferred. Another tube, H, may be employed to contain a ball safetyvalve, or its equivalent, for preventing excessive pressure within the vat. This also may be arranged and used for indicating the degree of pressure within. A pipe, I, provided with a suitable stop-cock, is used by which to draw ofi' or introduce the tan-liq uors. By this pipe, also, a pressure may be applied inside of the vat by means of the liqnor itself. I

In using this process, first, the vacuum or exhaustion is applied to the hides within the vat, either before or after theintroduction ot the tannin g-liquor; and, after the hides there by have been exhausted of the air, pressure br compression is applied within the vat to force the liquor into the pores of the hides previously vacated by the air. Thus the tannin is introduced into the interior of the hides or skins, and the tanning is effected both rapidly and thoroughly. This exhaustion and the subsequent compression are repeated on applying each successive liquor, or as often as required. 7

For small or thin skins the exhaustion or the compression alone may be applied, the succession or alternation of the exhaustion and compression not being required but for thick hides both processes are preferable or most completely effectual, and they shorten the time.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. A tan-vat constructed of two or more thicknesses of wood or equivalent material, with an intermediate thickness of lead or equivalent metal, and one or more thicknesses of water-proof paper, substantially as and for the purpose herein specified.

2. A varnish or coating composed of bees wax and spirits of turpentine applied to the metallic and paper thicknesses of the tan-vat, for the purpose herein specified.

S. The groove or depression h in the top of the vat, in combination with the cover A and its projecting packing-rim i, substantially as and for the purpose herein specified.

4. The packing-gasket I, when applied to the rim 6 of the cover A, so as to project laterally beyond the edges thereof, for the purpose herein specified.

5. The hard soap or equivalent plastic substance applied in the groove h of the vat, in combination with the rim '5 of the vat-cover-- and the gasket l there0n,f0r the purpose herein specified.

6. The agitators E Econnected together and arranged to vibrate vertically across the interior of the vat, in the manner as shown and described, and for the purpose herein specified.

CHAS. H. MANNING.

Witnesses:

J. S. BROWN, E. M. GALLAHER. 

